Chuck



July 12, 1949.

A. THALMANN CHUCK Filed Aug.l 20,1946

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Patented July 12, 1949 ENT OFFICE chuck Alfred Thalmann,Rorschacherherg, Switzerland, assignor to Rigid Limited,Rorschacherberg,

Switzerland Application August 20, 19416, Serial No. 691,768 InSwitzerland August 30, 1945 4 Claims.

My present invention relates to improvements in chucks of thequick-action type for securing bodies, e. g. a tool-holder or a tool onthe working spindle of a machine tool, and the objects oi my improvementare rst to ensure a highly accurate self-centering, a positive drive, aspeedy and fast clamping action, and second an easy and ready detachmentor slacking of the chuck elements at any load.

I attain these and related objects by the chuck shown, in two forms anda minor modification, in the accompanying drawing, in which Fig, 1 is anaxial section on line I-I of Fig. 3,

Fig. 2 a cross-section of Fig. 1, the clamping elements being in theactive, fast or grasping position,

Fig. 3 the same cross-section, the clamping elements being in theinactive, slacked or open position,

Fig. 4 a partial cross-section, similar to Fig. 3, of a slightly modiedform, and

Fig. 5 an axial section of a second form of chuck.

In the form shown in Figs. 1 3, a chuck socket 2 is secured on the headI of the working spindle of a machine tool by means of four screws 3engaged in threaded bushes d which in their turn are driven home inthreaded bores 5 of spindlehead I. The chuck socket 2 is internallythreaded, and an externally threaded clamping ring 1 is engaged therein.Further, a ball-retainer ring 8 is formed on the chuck socket 2, whereinfour grasping balls I0 are disposed in four grooves d.

The said grooves 9 are so adapted that the balls Ill are radially andaxially displaceable therein. The balls I Il however are Withheld in thegrooves 9 by the inner edges Il (Fig. 2) thereof so as to prevent theballs from dropping out of the chuck in its slacked position (Fig. 3)

'Ihe clamping ring 1 is provided with a peripheral locking groove I2which comprises a recess I3 for each ball I0. To limit the rotationalmovement of the clamping ring 1 in the chuck socket 2, a partialperipheral groove I1 is provided thereon Which is engaged by astop-screw I5. In the clamping ring 1, furthermore, bores I6 areprovided and which are adapted to be engaged by a stud wrench (notshown) for locking and slacking the chuck.

The tool base which may be a tool shank or tool holder shank I1 to beclamped fast comprises a conical portion I8 centered in the spindle-headI, and a peripheral clamping groove I9, co-acting with the balls Ill.The tool-holder and the chuck socket 2 are positively driven or caughtby means of a follower-block 2d engaged in a catch-groove 2l of thechuck socket 2 and, at the same time, in a catch-groove '22 of thetool-holder I1. A milling cutter 23 is secured to the tool-holder I1 bymeans of a screw 24.

In the slack-position (Fig. 3) of the clamping ring 1, the tool-holderI1 can be inserted into the chuck, since the balls lil in such positionmay roll from the groove I2 into the recesses I3. The latters depth,added to the thickness of the retainer-ring 8, corresponds to theball-diameter.` Having inserted the tool-holder I1, the clamping ring 1is turned from the slack-position intoclamping position (Fig. 2), thusbeing axially displaced on its threads. The balls thus are clamped fastin the grooves I2 and I 9 of the clamping ring 1 and the tool-holder I1respectively, so that the conical portion I8 of the latter is pressedfastly onto its seat and the tool-holder l1 thus centered in thespindle-head I. For slacking the chuck, the clamping ring 1 is turnedfrom the position shown in Fig. 2 into that of Fig. 3, upon which thetool-holder I1 may be readily withdrawn from the chuck.

The rotational movement of the ring 1 in its slack-position also may belimited, as shown in Fig. 4, by means of cross-grooves 3l disposed abovethe recesses I3 and.l in the threads S of ring 1, which grooves areengaged by a leaf-spring dog 32 secured on the outside of the chucksocket 2 upon reaching any one of the four inactive or slack positionsof the chuck.

The form of invention shown in Fig. 5 diiers from that of Figs. 1-3 inthat the chuck socket 2' comprises a shank 25 tting into the bore of thespindle-head I, and held therein, in a manner known, by means of a tierod (not shown). The chuck socket 2', here again, is taken along by-driver or follower-blocks 20. 'Ihe tool-holder 2S comprises/a clampinggroove I9 and a conical portion 21 centered in a conical bore oi thechuck-part 2. A drill 28 is inserted in the toolholder 21S. For takingalong the latter, a follower 29 is mounted on the shank 25 of the chucksocket 2 and is engaged in a recess 30 of the holder 2t.

While the chuck socket in the forms of invention described is secured tothe spindle-head, the latter itself also may be adapted as `chucksocket.

What I claim and ydesire to secure by Letters Patent, is:

1. A chuck of the class described, for holding a tool base having aperipheral groove comprising, a socket provided internally with threads,a ballretainer ring in the chuck socket for housing a plurality ciballs, an externally threaded clamping ring for engaging the thread ofsaid socket and provided with an inner peripheral groove with radialrecesses into which the said balls may enter in the slack-position ofthe clamping ring,

sai-d clamping ring being rotatable from the 5 slack-position into aclamping position by being axially displaced on its threads .toward thesaid balls which are clamped in the said clampingring groove on one handand in the peripheral groove of the tool base on the other hand so as tocenter and clamp the tool base.

2. In a chuck set forth in claim 1 and, a ballretainer ring for engagingthe .balls on their inner sides for preventing their ydroppingvout -inthe slack-position of the clamping ring.

3. In a chuck set forth inclaim .1;ar1'd.:abut ments on the clampingring for limiting tthe vrotational throw of the clamping ring.

4. A chuck according to claim 1 and in which the spindle is formed witha centering means bly which the tool ibase to be :clamped vis :centered,

and the chuck socket secured to the spindle-head,

the tool base, and the socket are driven by the spindle head by means ofdrivers or followers.

ALFRED THALMANN.

REFERENCES CITED The following referenlces are of record in the 'le ofthis patent:

UNITED STATES PATENTS

